Plasma membrane NADPH oxidases are major producers of reactive oxygen species (ROS) in plant cells under normal growth and stress conditions. In the present study the total activity of rice NADPH oxidases and the transcription of OsRbohA, which encodes an Oryza sativa plasma membrane NADPH oxidase, were stimulated by drought. OsRbohA was expressed in all tissues examined throughout development. Its mRNA was upregulated by a number of factors, including heat, drought, salt, oxidative stress and methyl jasmonate treatment. Compared with wild-type (WT), the OsRbohA-knockout mutant osrbohA exhibited upregulated expression of other respiratory burst oxidase homolog genes and multiple abnormal agronomic traits, including reduced biomass, low germination rate and decreased pollen viability and seed fertility. However, OsRbohA-overexpressing transgenic plants showed no differences in these traits compared with WT. Although osrbohA leaves and roots produced more ROS than WT, the mutant had lesser intracellular ROS. In contrast, OsRbohA-overexpressing transgenic plants exhibited higher ROS production at the intracellular level and in tissues. Ablation of OsRbohA impaired the tolerance of plants to various water stresses, whereas its overexpression enhanced the tolerance. In addition, a number of genes related to energy supply, substrate transport, stress response and transcriptional regulation were differentially expressed in osrbohA plants even under normal growth conditions, suggesting that OsRbohA has fundamental and broad functions in rice. These results indicate that OsRbohA-mediated processes are governed by complex signaling pathways that function during the developmental regulation and drought-stress response in rice.

The palladium-catalyzed Heck reaction is aw ellknown, Nobel Prizew inning transformation for producing alkenes.U nlike the alkenyl and aryl variants of the Heck reaction, the alkyl-Heck reaction is still underdeveloped owing to the competitive side reactions of alkyl-palladium species. Herein, we describe the development of ad eaminative alkyl-Heck-type reaction that proceeds through C À Nb ond activation by visible-light photoredoxcatalysis.Avariety of aliphatic primary amines were found to be efficient starting materials for this new process,affording the corresponding alkene products in good yields under mild reaction conditions.M oreover,t his strategy was successfully applied to deaminative carbonylative alkyl-Heck-type reactions.

Leaf rolling is considered as one of the most important agronomic traits in rice breeding. It has been previously reported that SEMI-ROLLED LEAF 1 (SRL1) modulates leaf rolling by regulating the formation of bulliform cells in rice (Oryza sativa); however, the regulatory mechanism underlying SRL1 has yet to be further elucidated. Here, we report the functional characterization of a novel leaf-rolling mutant, curled leaf and dwarf 1 (cld1), with multiple morphological defects. Map-based cloning revealed that CLD1 is allelic with SRL1, and loses function in cld1 through DNA methylation. CLD1/SRL1 encodes a glycophosphatidylinositol (GPI)-anchored membrane protein that modulates leaf rolling and other aspects of rice growth and development. The cld1 mutant exhibits significant decreases in cellulose and lignin contents in secondary cell walls of leaves, indicating that the loss of function of CLD1/SRL1 affects cell wall formation. Furthermore, the loss of CLD1/SRL1 function leads to defective leaf epidermis such as bulliform-like epidermal cells. The defects in leaf epidermis decrease the water-retaining capacity and lead to water deficits in cld1 leaves, which contribute to the main cause of leaf rolling. As a result of the more rapid water loss and lower water content in leaves, cld1 exhibits reduced drought tolerance. Accordingly, the loss of CLD1/SRL1 function causes abnormal expression of genes and proteins associated with cell wall formation, cuticle development and water stress. Taken together, these findings suggest that the functional roles of CLD1/SRL1 in leaf-rolling regulation are closely related to the maintenance of cell wall formation, epidermal integrity and water homeostasis.

A copper-catalyzed decarboxylative amination/hydroamination sequence of propargylic carbamates with various nucleophiles is described for the first time. It features an earth-abundant metal catalyst, mild reaction conditions, and high efficiency. Further treatments of the resultant key intermediates using an acid or a base in one pot enable the controllable and divergent synthesis of two types of functionalized indoles. Moreover, experiments to demonstrate the synthetic potential of this methodology are performed.

Oligopeptides were prepared from the guts of sea cucumber Stichopus japonicus by autolysis method. Optimum autolysis conditions for preparing oligopeptides from the guts of sea cucumber were determined by response surface methodology using a central composite rotatable design. The effects of two independent variables, namely temperature and pH, on the response of trichloroacetic acid-soluble oligopeptides (mg/g on dry basis) were investigated. Regression analysis indicated that more than 95 % of the variation could be explained by the fitted models. Temperature at 48.30°C and pH at 4.43 were found to be the optimal conditions to obtain oligopeptides from the guts of sea cucumber. The autolysis hydrolysates prepared at the optimized conditions were further fractionated into four major fractions (I-IV) by size exclusion chromatography on a Sephadex G-15 column. Fraction IV, which exhibited the highest DPPH radical scavenging capacity, Fe 2? -chelating ability and protective effect against hydroxyl radical-induced DNA damage, was then analyzed by ESI-MS for molecular mass determination and ESI-MS/MS for the characterization of peptides. Two tetrapeptides (Val-Thr-Pro-Tyr and Val-Leu-Leu-Tyr) and a hexapeptide (Val-Gly-Thr-Val-Glu-Met) were found to exhibit protective effects against hydroxyl radical-induced DNA damage. These results suggest that antioxidant oligopeptides derived from the guts of sea cucumber by autolysis method could be utilized for functional foods.